This invention relates generally to a method for determining a position and heading of a work machine at a work location and, more particularly, to a method for periodically checking the position and heading of the work machine by comparing with a known reference point.
Work operations which require the use of work machines, for example, earthworking operations requiring earthworking machines, must be performed with some degree of accuracy. However, the power required to perform the work, and the inherent harshness of the work environment, often make accuracy difficult to achieve. For example, it is often desired to dig trenches and the like using a work machine such as a backhoe loader. The backhoe loader must frequently be moved as the trench is created. If the heading of the backhoe loader shifts during excavation, as is often the case during digging, the operator must be careful not to drift off the intended course and dig the trench along the wrong boundaries.
Furthermore, work machines are becoming increasingly dependent on advances in technology. For example, electro-hydraulic work machines, such as the backhoe loader exemplified above, are increasingly automating many of the work functions that typically were performed by skilled operators. As an example, position and heading determining systems may be used to guide a work machine along an intended path. However, the harshness of the work environment, e.g., rocks, clay, and other obstructions in the soil, may shift the work machine off its determined heading, for example during trenching operations. Therefore, as the work machine moves to follow the trench line being created, the work machine may drift off its intended course, thus introducing errors in the excavation.
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the present invention a method for determining a position and a heading of a work machine having a work implement controllably attached is disclosed. The method includes the steps of positioning the work machine at a desired work location, determining an initial position and heading of the work machine in site coordinates, determining a position of the work implement relative to the work machine, positioning the work implement at a desired reference point, determining the position of the work implement at the reference point in site coordinates, periodically positioning the work implement at the reference point during work operations, and determining a new position and heading of the work machine as a function of the position of the work implement relative to the work machine.